Technical Field
This disclosure is directed to integrated circuits (ICs), and more particularly, to controlling transactions in a communications fabric implemented on an IC.
Description of the Related Art
Many modern integrated circuits (ICs), such as those that implement a system on a chip (SoC), include on-chip communications networks of various types. Such on-chip networks may include buses and other types of links between various functional circuit blocks of an IC. These on-chip networks may connect various functional circuit blocks to other functional circuit blocks on the same IC.
Various types of on-chip networks may be implemented on an IC. For example, functional circuit blocks in one type of on-chip network may be connected to other functional circuit blocks through crossbar switches. Bussed networks, in which a number of functional circuit blocks share a common bus are also possible. Peer-to-peer (P2P) networks may be implemented on some IC's as well, wherein each functional circuit block is connected directly to one or more other functional circuit blocks through dedicated connections. Transactions through P2P networks may in some cases be transferred through one or more intermediate functional circuit blocks during transit from a source to a final destination. On chip networks that implement more than one of these types of interconnect schemes are also possible and contemplated.
In order to save power, many functional circuit blocks on an IC may be placed in a sleep mode when idle. Communications between functional circuit blocks that are not in a sleep mode may continue to be conducted when others are in the sleep mode. However, the functional circuit blocks in the sleep mode are not available for communications until awakened and placed back into an active state.